Opus 4.6 is Anthropic’s strongest model for coding and long-running professional tasks. It is built for agents that operate across entire workflows rather than single prompts, making it especially effective for large codebases, complex refa…
Model details →Anthropic: Claude Opus 4.6 vs xAI: Grok 4 Fast
xAI: Grok 4 Fast wins on 3 of 6 axes — pricing and capability skew in its favour for most workloads.
Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model on xAI's [news post](http://x.ai/news/grok-4-fast). Reaso…
Model details →Side-by-side comparison
| Capability | Anthropic: Claude Opus 4.6 | xAI: Grok 4 Fast | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 1M | 2M | 🏆 xAI: Grok 4 Fast |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $5.00 | $0.20 | 🏆 xAI: Grok 4 Fast |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $25.00 | $0.50 | 🏆 xAI: Grok 4 Fast |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | Yes | Yes | Tie |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is Anthropic: Claude Opus 4.6 better than xAI: Grok 4 Fast?
xAI: Grok 4 Fast wins on 3 of 6 axes — pricing and capability skew in its favour for most workloads.
What's the price difference between Anthropic: Claude Opus 4.6 and xAI: Grok 4 Fast?
Input: $5.00 vs $0.20 per 1M tokens. Output: $25.00 vs $0.50 per 1M tokens.
What context windows do Anthropic: Claude Opus 4.6 and xAI: Grok 4 Fast support?
Anthropic: Claude Opus 4.6 supports up to 1M tokens. xAI: Grok 4 Fast supports up to 2M tokens.
Do both Anthropic: Claude Opus 4.6 and xAI: Grok 4 Fast support tool calling?
Anthropic: Claude Opus 4.6: yes. xAI: Grok 4 Fast: yes.